Large wheels such as, for example, aircraft landing gear wheels require balancing to ensure an equal distribution of mass to prevent, among other things, uneven tire wear and undesirable moment of rotational inertia. In general such wheels are imbalanced because of variations in weight of individual components on the wheels such as inflation valves, safety relief valves, tire pressure sensing valves and heat shields. Other variations in weight may be attributed to geometry variables throughout the wheel and manufacturing capabilities to meet specified tolerances.
Wheel balancing remains a necessity for many large wheels such as aircraft wheels. Present large wheels balance components by adding weights to parts of the wheel to achieve an equal distribution of mass. However, such methods increase the cost of manufacture since they require additional hardware such as, nuts and bolts and machining, to attach such weights. Further, the wheel attachment features for weights add unnecessary weight to the wheel if wheel balancing is not required. Finally, the attachment process for wheel weights may cause structural weakness in various parts of the wheel.
A large wheel brake system may use a multi-disc brake assembly. The brake assembly has a number of rotors attached to the wheel which together rotate around an axle, and a number of stators attached non-rotatably to the brake assembly and interleaved with the rotors. The brake assembly is fixed typically to the landing gear strut. The brake assembly displaces hydraulic pistons against a pressure plate to squeeze together the spinning rotors with the stationary stators and thereby producing torque to decelerate the rotational motion of the wheel.
Rotor drive keys are commonly used to connect the rotors with the wheel. The rotor drive keys are mounted on the interior surface of the wheel well, at a predetermined radial distance from the brake assembly. The rotor drive keys engage the rotors via slots on the circumferences of the rotors. Typically, the rotor drive keys are made from hardened and tempered steel to provide a high tensile strength since during braking, the rotor drive keys must withstand substantial braking torque as the rotors engage the stators.